1. Field of the Invention
The present invention relates to a video processing method, an encoding device, a decoding device, and a data structure for facilitating layout of a restored image frame.
2. Description of the Related Art
A conventional videoconference system, such as that shown in FIG. 1, is an example of a video processing system. A plurality of source image frames 9011˜901n included in a real-time image sequence are compressed into video signals by a video encoder 91. The video signals are then transmitted via a network 8 to a video decoder 92. The video decoder 92 decodes the video signals for recovery into a series of output image frames 9021˜902n. 
In the conventional videoconference system, the entire process from inputting the source image frames 9011˜901n into the video encoder 91 to transmitting the resulting signals via the network 8 for output to the video decoder 92 is conducted using a single fixed resolution. Therefore, if the bandwidth of the network 8 is abruptly reduced, and the encoding bit rate (data amount of each frame×frame rate) exceeds the bandwidth, this will result in intermittent and/or unclear pictures at the receiving end.
One conventional approach used to overcome this problem is that in which the resolution of the source image frames 9011˜901n is initially set sufficiently low so that any unexpected drop in the bandwidth of the network 8 will not result in an encoding bit rate that exceeds the bandwidth. However, such an approach is not ideal since the resulting output image frames 9021˜902n will be of a low quality. According to another conventional approach, bandwidth detection is performed prior to operation of the videoconference system, after which the resolution to be employed by the video encoder 91 is determined based on the detected bandwidth. However, no further adjustment in resolution is contemplated when such a technique is employed.
A conventional video monitor system is another example of a video processing system. In the conventional video monitor system, input is received typically from a plurality of image sources, and a video encoder with a fixed image resolution is used for each image source. The large number of video encoders involved in, for example, a 16- or 32-channel video monitor system (i.e., one video encoder for each channel) results in high system costs and complexity. Moreover, a separate bit stream is transmitted over a network for each video encoder, which is burdensome on the network. Finally, as with the conventional video conference system, the conventional video monitor system is unable to effectively cope with the problems associated with abrupt reductions in network bandwidth.